Application Design And Architecture

Contents

• 5.1 Introduction
• 5.2 Downward interfaces
  • 5.2.1 The frustrum
  • 5.2.2 Graphical output
• 5.3 Calls to Parasolid functions
  • 5.3.1 Managing Parasolid errors

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5.1 Introduction

When integrating Parasolid into your product, some of the design decisions you need to make are constrained by the requirements of Parasolid itself. Your ultimate aim is to make calls to Parasolid routines from within your own application code in order to perform solid modeling operations. In order to do this, you need to supply code that ensures that your application and Parasolid can interact correctly. This chapter gives you an overview of the code you need to supply before you can start making calls to Parasolid routines from your own code.

Figure 5-1 shows how Parasolid interacts with a typical application:

Figure 5-1 How Parasolid interacts with a typical application

The code that you need to supply for integration with Parasolid falls into two categories:

• Downward interface code.
• Calls to Parasolid functions.

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5.2 Downward interfaces

Your application controls all interaction between Parasolid and the operating system. The parts of your application that deal with this are referred to generically as downward interfaces. You usually need to have two parts to your downward interface:

• The frustrum
• Graphical Output (GO) - required for displaying models

Because Parasolid itself makes calls to routines in these downward interfaces, they need to be registered with Parasolid before your application can call any Parasolid functions.

5.2.1 The frustrum

The frustrum is a suite of functions that deals with:

• File handling: Saving and retrieving Parasolid part files and other data.
• Memory management: Allocating memory for internal calculations and data structure storage.

5.2.2 Graphical output

If your application needs to display models - whether by rendering them on screen, or printing them to a plotter or laser printer - you must provide GO functions for Parasolid to use.

Parasolid calls the GO functions whenever your application calls a Parasolid rendering function in order to draw one or more parts. The GO functions encapsulate the graphical information output by Parasolid, and pass it to a graphics library (that you also provide) in order to render the image.

You can write the graphics library yourself, or you can use a third party library such as OpenGL or DirectX.

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5.3 Calls to Parasolid functions

Parasolid is supplied as a library of functions and is designed as a toolkit of component software that you can embed into your product. The Parasolid API is called the PK. The PK contains functions for:

• Building, modifying, and combining parts
• Finding out information about the properties of parts (such as mass, geometric information, or rendering information)
• Functions for saving parts, and loading parts back into Parasolid

See Chapter 9, “PK Interface Programming Concepts”, for an introduction to using functions in the PK.

5.3.1 Managing Parasolid errors

Your application must be able to handle errors returned by PK functions. See Section 6.7, “Error handling”, for more details.

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